Function sourceview5_sys::gtk_source_gutter_lines_get_iter_at_line

pub unsafe extern "C" fn gtk_source_gutter_lines_get_iter_at_line(
    lines: *mut GtkSourceGutterLines, 
    iter: *mut GtkTextIter, 
    line: c_uint
)

This is supported on crate feature v5_0 only.